1. Field of the Invention
This invention relates to frozen comestible freezer/dispensers, and particularly to a modified liquid/air proportioner or carburetor containing check valve means for preventing backflow of discharged materials and air due to an imbalance of pressure which may occur when withdrawing frozen comestible from the freezer chamber.
2. Description of Related Art
U.S. Pat. No. 4,221,117, assigned to the same assignee as the present application, disclosed a prior art device for proportioning a liquid comestible with air enroute from a liquid comestible tank to a freezing chamber in which the liquid comestible and air are blended and cooled to a serving consistency. The patent disclosed an improvement over earlier devices having a similar function. The patented improvement eliminated adding air to the liquid comestible via a single tube which often created air bubbles in the liquid comestible in the combined air and liquid fill tube. The patented improvement accomplished this by utilizing a pair of tubes wherein the aerator proportioner, or carburetor, had a feed tube solely for liquid comestible and an air tube solely for air.
Although the U.S. Pat. No. 4,221,117 disclosure provided a distinct improvement over the single tube devices, when placed in an actual working environment, there have been instances noted where when withdrawing the product there is created a low pressure in the freezer/dispenser unit tending to draw the product and air into the unit in undesired proportions due to the unequal pressures.